SECTION 5. RESOURCE CORE 1: FUNCTIONAL ASSESSMENT CORE (FAC) Although the prevalence of chronic disability in older individuals remains on the decline in the United States, the total number of individuals over the age of 65 with chronic disability is increasing (1, 2). Presently, limitations in mobility affect almost one in four individuals over age 65 and three quarters of those living in nursing homes (3). In non-disabled older individuals, limitations in mobility in such tasks as climbing stairs, and walking across a room have been defined as "mobility disability" (4). To capture and assess mobility limitations in the elderly, performance tests of functional capacity have been developed and have been shown to be predictive of incident disability, institutionalization, and mortality (4, 5). In particular, walking ability alone, as measured by gait speed during a 4 M walk test, has been shown to be a strong predictor of subsequent ADL disability and mobility disability (6). In addition, validated highly reliable instruments to assess components of physical disability have also been developed and implemented in observational studies and clinical trials. More recently, testing protocols in selected animal models (rats, mice) have been developed to assess important endpoints related to impairments and functional limitations in these species. The physical function assessment core seeks to provide the necessary infrastructure to perform standardized, valid and reliable measures physical impairments, function, and disability across the array of clinical studies supported or associated with the Tufts-BU OIAC. In addition, this same core will provide support for the assessment of physical impairments and function across an array of basic (animal model) studies associated and supported by or affiliated with the Tufts-BU OAIC. The leadership of this core has collaborated extensively over the past ten years, has extensive experience in the application of these measurements across a wide range of cross-sectional and intervention studies in older adults, and is uniquely cross-trained in the assessment of muscle impairments and functioning in animal models. This uniquely structured interdisciplinary core will provide a forum for performing these validated standardized assessments and to further refine and expand the availability of new techniques to assess physical functioning and functional capacity across a range of species from rodents to humans. 1. Provide a focal point for interdisciplinary collaboration by Center investigators in the development, evaluation, and application of new and existing tools and instruments to assess muscle impairments, functional limitations, and disability in older adults and function promoting therapies. 2. Promote and foster the development and refinement of tools and instruments to assess muscle performance and physical functioning in animal models of aging. 3. Standardize equipment and operating protocols for the assessment of muscle performance &functional limitations in human and animal studies. Implement and maintain personnel training and certification for the application of standardized muscle performance and functional limitations testing protocols. Establish and maintain equipment calibration for use across all Center studies. A wide array of basic studies and clinical trials would benefit from the collective resources of this core. Increasingly, due to pressure from regulatory agencies and a defined need to assess more distal outcomes in trials of function promoting therapies in older adults, treatments of muscle loss (sarcopenia) have been directed to assess therapeutic efficacy by assessing subjective symptomatology (eg: fatigue, energy, difficulty in activities of daily living) and objective measures of physical functioning (eg: gait velocity, chair stand capacity, stair climbing performance). In addition, novel therapeutic interventions targeted at specific pathophysiological changes and impairments in older individuals with functional limitations must continue to be examined. Finally the emergence of the ability to genetically modify laboratory rodents has increased the need to adequately assess the phenotype of these animals with respect to physical impairments such as voluntary muscle strength and functional limitations such as gait, maize performance and balance. The key personnel affiliated with the FAC are uniquely qualified to provide the necessary support and infrastructure for this core.